Microdevice and method for transdermal delivery and sampling of active substances

ABSTRACT

A system and method of using a high-aspect ratio microdevice for treating, preventing or ameliorating a medical condition is provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation in part application of U.S. patentapplication Ser. No. 11/961,816, filed on Dec. 20, 2007, which claimsbenefit of U.S. Provisional Patent Application No. 60/876,948 which wasfiled on Dec. 22, 2006. The contents of application Ser. No. 11/961,816and provisional application 60/876,948 are incorporated by referenceherein in their entirety.

TECHNICAL FIELD

The present application relates to a microdevice for transdermaldelivery of an active substance and methods of using the same.

BACKGROUND

Major reasons for the success of transdermal delivery were the avoidanceof first-pass metabolism and ease of use. This increases drugbioavailability in comparison to other delivery methods. TransdermalDrug Delivery Systems (DDS) can also deliver drugs at a steady rate toachieve a sustainable release, which is an additional advantage.However, transdermal drug delivery methods have their drawbacks. Mostimportant is the fact that conventional transdermal system (TTS)technology is only suited for delivering relatively small drugs acrossthe skin. It also suffers from slow onset, because of the outer skinbarrier layer, stratum corneum, that limits the through skin drugtransport.

New transdermal drug delivery methods are therefore required to drivefuture growth in transdermal product markets. Biological products wouldalso profit greatly from new, non-invasive delivery technology toreplace hypodermic needle injection that is the current standard. Theoriginal players in the transdermal field failed to introduce suchimprovements, which were then introduced by a number of innovatorcompanies.

Broadly speaking, two different new approaches for transdermal drugdelivery are currently being pursued: (1) nanoporation/minimum abrasionusing a physical device, and (2) nanocarriers using lipid-encapsulatedformulation. Sonoporation, thermoporation) use of very fine and shortneedles belong to the former; ultradeformable carriers (such asTransfersome®, Ethosomes® or fluid liposomes) are examples for thelatter. Any of these can deliver small or large molecules across theskin. Some examples of transdermal delivery are described in U.S. Pat.Nos. 7,094,423; 7,049,140; 7,041,870; 7,037,499; 7,034,126; 7,033,598;7,014,855; 6,991,805; 6,982,084; and 6,979,729.

However, there is a continuing need for an improved, disposabletransdermal delivery device for effective delivery of substances in acontrolled manner.

SUMMARY

It is an objective of this subject matter to combine both nanocarriersand nanoporation methods to create new transdermal drug deliveryvehicles.

It is a further objective of this subject matter to disclose amechanical applicator to facilitate the application of nanoporationdevices.

It is a further objective of this subject matter to disclose a wetdevice/drug combination method to deliver drug transdermally. Thedevice/drug combination includes, but is not limited to any one or moreof the following: (1) pre-treating the mammal using the device, thenapplying the drug to the mammal; (2) applying the drug to the mammal,then treating the mammal with the device; (3) temporarily anchoring thedrug onto the device, then treating the mammal with the device/drugsystem.

It is a further objective of this subject matter to provide an occlusivelayer useful for increasing penetration of an active agent applied tothe skin after nanoporation and/or application of the wet formulation.

In some embodiments, the method of delivering an agent described hereinincludes: (1) applying an applicator to a microdevice to cause themicrodevice to contact an area of skin of a mammal (e.g., patient) togenerate a prepared area of skin comprising a plurality of nanopores ornanochannels through the stratum corneum in a defined area of skin, (2)applying a wet formulation comprising the agent to the area of skinbeing prepared either before or after the microdevice has generated theplurality of nanopores or nanochannels in the prepared area of skin, (3)applying an occlusive layer over the agent and directly on the preparedarea of skin such that the occlusive layer prevents air from coming intocontact with the prepared area of skin following the removal of theapplicator and microdevice from the skin, and (4) causing an effectiveamount of an agent to deliver to the patient through the nanopores ornanochannels in the stratum corneum. The microstructure can be coatedwith a composition comprising the agent. In some embodiments, thecausing is by applying a wet formulation including liposomenanoparticles encapsulating the agent and causing the agent to transportthrough the stratum corneum into the mammal.

In some embodiments, the present subject matter provides an applicatorof the microdevice described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show two preparations of liposome nanoparticlescontaining docetaxel.

FIG. 2 shows penetration (%) of docetaxel in elastic liposomes with orwithout microneedle and with or without an occlusive layer.

FIG. 3 shows fluorescence labeled docetaxel encapsulated within elasticliposome nanoparticles being successfully transported through skin.

FIG. 4 shows delivery of interferon via different methods.

FIG. 5 shows delivery of interferon with a dry formulation.

FIG. 6 shows a graph of Trans-Epidermal Water Loss with or withoutmicroneedle application.

FIG. 7 shows a graph of serum insulation concentration with an occlusivelayer applied.

DETAILED DESCRIPTION

The present subject matter provides high-aspect-ratio microstructures(HARMS) and methods of using the same. The present subject matter alsoprovides methods of using the device for transdermal delivery of drugs,vaccines, diagnostic agents and cosmetic substances and sampling of bodyfluids for treating, preventing, or ameliorating a medical condition ofa mammal such as a human being. In some embodiments, the methodcomprises treating a topical site of a mammal using a device, andapplying an effective amount of an agent to the topical site to allowthe agent to penetrate into the body of the mammal. The device caninclude an array of microstructures. The microstructure can have anaspect ratio of about 5:1, 10:1, 15:1, 20:1 or higher.

In some embodiments, the present subject matter provides a system fortopical or systemic delivery of an agent for a medical condition in amammal (e.g., a patient). The system comprises: (1) a microdevicecomprising an array of microstructures, (2) an applicator for applyingthe microdevice to an area of skin of a patient to generate a preparedarea of skin comprising a plurality of nanopores or nanochannels instratum corneum of the prepared area of skin, and (3) a deliverymechanism for causing the agent to be delivered to the mammal throughthe nanopores or nanochannels in the stratum corneum of the preparedarea of skin. In some embodiments, the microdevice can comprisenanoscale tips and microscale body that can have an aspect ratio ofabout 5:1, 10:1, 15:1, 20:1 or higher.

In some embodiments, the present subject matter provides a method ofdelivering an agent for a medical condition to a mammal. The methodcomprises: (1) applying an applicator to a microdevice to cause themicrodevice to contact an area of skin to generate a prepared area ofskin comprising a plurality of nanopores or nanochannels through thestratum corneum of the area of skin, (2) applying a compositioncomprising the agent to the prepared area of skin, (3) applying anocclusive layer over the area of skin, and (4) causing an effectiveamount of the agent to deliver to the patient through the nanopores ornanochannels in the stratum corneum.

In some embodiments, the method of delivering an agent described hereinincludes: (1) applying a composition comprising the agent to an area ofskin, (2) applying an applicator to a microdevice to cause themicrodevice to contact the area of skin to generate a plurality ofnanopores or nanochannels through the stratum corneum of the area ofskin, (3) applying an occlusive layer over the area of skin, and (4)causing an effective amount of the agent to deliver to the patientthrough the nanopores or nanochannels in the stratum corneum.

In some embodiments, the method of delivering an agent described hereinincludes: (1) applying an applicator to a microdevice to cause themicrodevice to contact an area of skin of a mammal (e.g., patient) togenerate a prepared area of skin comprising a plurality of nanopores ornanochannels through the stratum corneum of the area of skin, (2)applying an occlusive layer over the area of skin, and (3) causing aneffective amount of an agent to deliver to the patient through thenanopores or nanochannels in the stratum corneum. The microdevice can becoated with a composition comprising the agent. In some embodiments, thecausing is by applying a wet formulation including elastic liposomescomprising liposome nanoparticles encapsulating the agent and causingthe agent to transport through the stratum corneum into the mammal. Insome embodiments, the wet formulation does not include elasticliposomes.

As used herein, the term “composition” sometimes can be usedinterchangeably with the term “formulation.” The term “wet formulation”refers to any form of wet formulation. In some embodiments, a wetformulation can be a skin patch, cream, ointment, or lotion. In someembodiments, the wet formulation can include elastic liposomescomprising liposome nanoparticles encapsulating an agent. In someembodiments, the wet formulation can include an agent, but not elasticliposomes.

As used herein, the term “agent” refers to any diagnostic, therapeutic,or preventive agents. The term “agent” is sometimes interchangeablyreferred to as “active agent,” “bioactive agent,” or “active substance.”

Skin Structure

Skin has a biological barrier called stratum corneum in its outer layer.This layer of about 10-25 microns thick prevents most of the moleculesfrom penetrating through the skin. The layer below the stratum corneumis called viable epidermis. Epidermis is between 50 to 100 micron thick.The viable epidermis layer has no blood vessels and the molecules inthis layer can be transported to and from the dermis, a layer under theviable epidermis, which is between 1 to 3 mm thick. There are bloodvessels, lymphatics and nerves in dermis layer. To date, for example, askin patch is only able to deliver drug molecules of less than 500 Da.In addition, these small molecules are typically limited to hydrophobicones.

Requirement of Delivery of Drugs, Vaccines and Cosmetic Substances

Successful transdermal delivery of therapeutic drugs, vaccines andcosmetic substances needs a way to transport molecules, especially largemolecules, through the skin barrier, i.e., the stratum corneum. Thesubstance can be delivered into the skin in any form acceptable forpharmaceutical requirements, but a gel composition is preferred toachieve controlled release of the active ingredient(s).

The microdevice described herein can be used for effective transdermaldelivery of an agent or a combination of agents. The microdevice can bea microdevice array comprising a plurality of microstructures formed ofa metallic, semi-conductor, glass, ceramic, or polymeric material. Insome embodiments, the microdevice can be microneedle, microknife, ormicroblade. In some embodiments, the microdevice comprisingmicrostructures having a nanoscale tip or edge and a microscale body.

Microdevices

The microdevices described herein can be any of microneedles,microblades, microknives, or combinations thereof. As used herein, theterm “microneedle” means an elongated element having a ratio of lengthto largest cross-sectional dimension, of at least about 1:1 or higher.The microneedle may have a regular or irregular cross-sectional shape,such as, for example, circular, elliptical, geometric, or a combinationthereof. The needle may optionally include one or more edges runningpart of or all of the length of the needle's central axis of elongation.The term “microneedle” may also refer to a means that is sufficientlysharp to puncture skin tissue, such as the stratum corneum, to therebygenerate nanoconduits.

As used herein, the terms “microblade” and “microknife” both mean anelongated element that is substantially long and thin. For example,having a ratio of length to thickness, of at least about 2:1 or higher.Each microblade includes two surfaces that meet at a single long edge.The length of the edge may be oriented parallel to the skin surface,perpendicular to the skin surface, or at an angle to the skin surface. Amicroblade with an edge that is significantly parallel to the skinsurface may generate a nanoconduit in the skin that is an elongatedopening or channel along the surface of the skin that has a narrow widthand a depth into the skin as described above for nanoconduits. Amicroblade with an edge that is significantly perpendicular to the skinsurface may generate a nanoconduit in the skin that is an elongatedopening in the skin that has a narrow width, or the nanoconduit may havemore of a puncture shaped volume wherein the opening has narrow widthsin all directions. The terms “microblade” and “microneedle” may alsorefer to a means having an elongated edge that is sufficiently sharp topuncture skin tissue, such as the stratum corneum, to thereby generatenanoconduits. A microdevice may comprise one or more microneedles,microblades, or microknives.

Aspect-ratio is defined as the ratio of the depth or height of astructure to its lateral dimension. High-aspect-ratio microstructures(HARMS) typically have an aspect ratio higher than about 5:1 and theymay be useful for a variety of purposes. In the current subject matter,the tip of microneedle 6 or the edge of the microblade and microknife 6needs to be sharp in order to lower the insertion force, while the bodyof microdevice 7 should be high enough to allow it to completelypenetrate stratum corneum. A typical size of the needle tip or width ofedge on microblades and microknives is smaller than 10 microns,preferably smaller than 5 microns and the height of the microdevices ishigher than 20 microns, preferably higher than 50 microns. The aspectratio of these microdevices, in a preferred embodiment of the currentsubject matter, are higher than 10:1 with the size of the tip and edgesmaller than 5 microns and the height of microdevices higher than 50microns. HARMS can thus be used to fabricate microdevices includingmicroneedles, microblades, and microknives for drug delivery throughskin or body fluids extraction out of skin. Another example of HARMS isnanochannels for microfluidic manipulation and transport. HARMS istypically made by Micro-ElectroMechanical Systems (MEMS) andnanofabrication technology that involves a number of thin filmdeposition, photolithography, etching and electroplating, injectionmolding, hot embossing, self-assembly, as well as LIGA process.

A “microneedle array” as used herein refers to a localized arrangementof more than one microneedle, microblade, microknife, or combinationsthereof on a surface. The localized arrangement may comprise regular orirregular patterns of the microneedles, microblades, or microknives. Forexample, microneedles and/or microblades may be arranged in rows, inrandom formation, or a combination thereof. The microneedle, microblade,microknife, or microneedle array may be present on one or more surfacesof an applicator device.

The microdevice can further include microchannels and microreservoirs.The microdevice or microneedle array may also optionally comprisehollows, voids, non-smooth textures, and/or cavities. One possible useof the hollows, voids, non-smooth textures, and/or cavities is as a siteto localize, concentrate, or deliver the agent in embodiments where theagent is to be applied to the skin simultaneously with the generation ofthe nanoconduits. In some embodiments, the microneedles or microbladescomprise hollow channels for delivering an agent via diffusion or activeinjection, for example from a reservoir. In other embodiments, themicroneedles or microblades do not comprise hollow channels fordelivering an agent via diffusion or active injection. Some examples ofthe microdevice are described in U.S. application Ser. Nos. 10/908,584,filed on May 18, 2005 and Ser. No. 11/510,078, filed on Aug. 25, 2006.The teachings of both applications are incorporated herein in theirentirety by reference.

Materials and Device Sterilization

The microdevices can be made of many different materials or theircombinations, including metals, ceramics, polymers and glass. Examplesof the materials are titanium, stainless steel, nickel, alloy ofnickel-iron, silicon, silicon oxide, glass, polymethyl methacrylate(PMMA), polyaryletherketone, nylon, PET, poly(lactic acid),poly(glycolic acid) (PGA), poly(lactic-co-glycolic acid) (PLGA),polycarbonate, and polystyrene. It should have enough mechanicalstrength to penetrate skin without break and buckle while ensuredelivery of drugs, or collect of biological fluids. They can besterilizable using established protocols (see, for example, moist heat,ethylene oxide or radiation sterilization as stated by ANSI/AAMI/ISO11134:1993, ANSI/AAMI/ISO 11135:1994 and ANSI/AAMI/ISO 11137:1994, thecontents of which are incorporated herein by reference in theirentirety).

Elastic Liposome

An elastic liposome is an artificial vesicle designed to be like a cellvesicle, and used to deliver drugs or genetic material into a cell. Itsbounding membrane is more flexible than that of a liposome, allowing itto deform and pass through openings in a barrier, such as the skin,whose diameters are much smaller than the average vesicle size. Anelastic liposome is an at least bi-component, most often vesicular,aggregate. The main functional characteristic of the aggregate is theextreme flexibility and permeability of its bilayer-like membranecoating. Its basis is the interdependency of local membrane shape andcomposition, which makes the bilayer self-regulating andself-optimising. The bilayer is thus capable of stress adaptation, vialocal and reversible bilayer component demixing. All this makes anelastic liposome into a tool suitable for non-invasive and targeted drugdelivery, for example across intact skin.

Another beneficial consequence of high bilayer flexibility is theincreased elastic liposome affinity to bind and retain water.Ultradeformable elastic liposome vesicles put in a dry environmenttherefore seek to find water richer region. This forces elastic liposomevesicles applied on open skin to penetrate the skin barrier in a searchfor adequate hydration. The resulting vesicle migration is a consequenceof continuous bilayer adaptation and deformation, but must notcompromise unacceptably either the vesicle integrity or the protectiveskin barrier properties in real-life applications.

A basic elastic liposome is composed of one natural amphiphat (such asphosphatidylcholine) that tends to self-aggregate into vesicles. Thelatter are then supplemented by at least one bilayer softener (e.g. abiocompatible surfactant). The vesicle-like elastic liposome thusnormally possesses an aqueous core surrounded by a complex, very fluidand adaptable lipid bilayer. In its basic organization broadly similarto a simple lipid vesicle (also called liposome), an elastic liposomediffers from the latter by its more flexible and permeable, “softened”bilayer membrane. An elastic liposome vesicle can consequently changeshape readily and easily by adjusting relative concentration of its twocomponents in the bilayer to the local stress experienced by the complexbilayer. This can be observed indirectly by studying stress- ordeformation-dependent vesicle bilayer elasticity or permeability. In asingle experiment, the same goal can be achieved by determining thepressure dependency of elastic liposome suspension-flux through anano-porous filter (with the pores considerably smaller than the averagevesicle size). The rate of resulting transport must grow with drivingforce (head pressure) non-linearly (often sigmoidally) until maximumflow is reached. For an ideal elastic liposome, experiencing no frictionin pores, the maximum flow is equivalent to the flux of the suspendingliquid measured with a similar trans-filter pressure, and the minimumpressure required to attain good transport is a measure of bilayerflexibility. The observed functional dependency of suspension fluxversus pressure can therefore be used to derive bilayer elasticity andflexibility, as well as permeability, based on theoretical descriptionof the underlying enforced transport, viewed as an activated transportprocess.

Liposome Carrier

In some embodiments, the delivery formulation described herein includesa carrier that comprises elastic liposomes. In some embodiments, theliposomes can be nanoparticles containing lipid-encapsulated therapeuticagents. The liposomes or nanoparticles are complex, most oftenvesicular, aggregates. In some embodiments, the liposomes ornanoparticles can be optimized to attain flexible and self-regulatingmembrane, which makes the vesicle very deformable. These liposomes ornanoparticles can be typically applied on the skin and can be engineeredto achieve high drug concentration at or near the site of application,diminish local or systemic adverse side effects, and often increase drugpotency. The term “high drug concentration” refers to a localconcentration enough to achieve desired therapeutic effects withoutincur significant side-effect.

Liposome nanoparticles can be formed by known method in the art.Generally, the method for forming liposome nanoparticles can be thinfilm dispersion, reverse-phase evaporation, alcohol infusion, extrusionwith or without pressure, which are known in the art (see, e.g., PlanasM. E.; Gonzalez M. E.; Rodriguez L. et al. Noninvasive percutaneousinduction of topical analgesia by a new type of drug carrier, andprolongation of local pain insensitivity by anesthetic liposomes.Anesth. Analg 1992. 75(4):615-621; Gregor Cevc, Gabiele Blume, AndreasS, et al. The skin pathway for systemic treatment with patches and lipidbased agent carries[J] Advanced Drug Delivery Reviews, 18:349 (1996);Gregor Cevc, et al., Ultradeformable lipid vesicles can penetrate theskin and other semi-permeable barriers unfragmented. Evidence fromdouble label CLSM experiments and direct size measurements Biochimica etBiophysica Acta 1564:21-30 (2002); G. Cevc, et al., Overcomingsemi-permeable barriers, such as the skin, with ultradeformable mixedlipid vesicles, Transfersomes® liposomes or mixed lipid micelles.Langmuir, 19:10753-10763 (2003); Gregor Cevc, Lipid vesicles and othercolloids as drug carriers on the skin Advanced Drug Delivery Reviews56:675-711 (2004)).

FIGS. 1A and 1B show two preparations of liposome nanoparticlescontaining docetaxel.

Method of Use

The device described herein can be used for transdermal delivery of anagent or a combination of agents to treat, prevent, or ameliorate a bodycondition in need of treatment. The method generally includes treating askin site of delivery with a microdevice described herein, and deliveryan agent to the body of a mammal (e.g., a user or patient).

Skin is an elastic tissue that deforms when a force is applied. Anapplicator and method is described for applying amicroneedle/nanoporation device, including a plurality of microneedleswith a gentle impact. The method is used to improve transport of anactive agent through skin barrier.

It is noteworthy that the prior art uses drug coated tip or hollowmicroneedles to deliver drug through skin. The present subject matterprovides for a method that includes, e.g., pre-treating skin bymicroneedle array to generate a pre-treated area of skin, and applyingto the pre-treated area a wet formulation to allow a therapeutic agent(e.g., drug) or a combination of therapeutic agents to transport throughskin. The wet formulation can be in the form of lotion, cream, gelpatch, ointment or skin patch. In some embodiments, an occlusive layeris applied over the wet formulation to aid in transporting thetherapeutic agents through skin.

In some embodiments, the agent can be included in the microdevice as acoating with or without a carrier. In these embodiments, the agent canbe delivered with the microdevice being attached to the site of deliveryuntil a desired quantity or duration of delivery is achieved.

In some embodiments, the agent can be separate from the microdevice. Inthese embodiments, the skin site chosen for delivery the agent can bepre-treated with the microdevice. The agent can then be applied to theskin site of delivery to allow the agent to penetrate into the body of auser or patient.

The body condition can be a medical condition or a cosmetic condition.Representative medical conditions include, but are not limited to, AIDS,breast cancer, melanoma, liver cancer, lung cancer, blood cancer,pituitary tumors, other cancers, flu, infection, blood disease, cardiacdisease, back pain, neck pain, body pain, general pain, arthritis,osteoporosis, headache, depression, smoke, alcoholic, overweight andobesity, menopause, facial hair growth, balding, polycystic ovarysyndrome, need of inoculation, need of anesthetics and in particulardermal disease. Representative cosmetic conditions include, but are notlimited to, skin aging, skin wrinkle, dark spot, skin discoloration,moisturizing, skin lightening, skin whitening, skin firming, skinlifting, acne, wart, infection, irritation, dry skin and oily skin.

The present microdevices are designed as disposable or re-usabledevices. In one embodiment, the microdevices are disposable. Dependingon whether the microdevices have coating of active substances on them ornot, there are three categories of applications in the delivery ofdrugs, cosmetic substances and vaccines in the preferred embodiment.

For delivery of a drug, vaccine or cosmetic substance, in oneembodiment, the microdevices can be used to perforate or scratch stratumcorneum. They are then removed immediately and a formulation of anactive substance such as a lotion, cream, gel patch, ointment or skinpatch with the active substance is applied to the microdevice treatedarea right away. The formulation will stay on the skin for a pre-definedperiod, providing sustainable controlled release of an agent such as adrug, or a combination of agents.

Another embodiment is to store the active agents, as defined below, inthe substrate and rely on passive diffusion when the microdevice is intouch with skin.

In yet another embodiment, one can apply the drugs, in the forms of gel,cream, ointment and lotion, or a combination of those forms, to desiredtreating area on the skin, then treat the skin area with drug using thesaid microdevice.

In yet a further embodiment, one can pre-coat microneedle shaft with acomposition that contains active substances. The coated microneedles areapplied to the skin and stay on the skin for the entire period oftreatment. The rate of through skin transport can be measured using invitro or in vivo methods known in the art.

Applicator

In some embodiments, an area of skin can be pre-treated by themicrodevice described herein using an applicator. An “applicator device”or “applicator” as used herein refers to a device or object used togenerate nanoconduits in the skin. The applicator preferably comprises adriving structure, element, mechanism, and/or means for generatingnanoconduits in the skin. The applicator is preferably used inconjunction with a surface, patch, or reservoir comprising an agent tobe delivered. The applicator helps to both deliver agent and generatenanoconduits at a single predetermined skin area at a time. Accordingly,in an alternative embodiment, the applicator may simultaneously generatenanoconduits in the skin area and apply a pre-applied agent.

In some embodiments, the applicator may employ vibration of one or morefrequencies to create an impact force to generate the nanoconduits. Forexample, in one embodiment, the applicator may contain an exchangeablehead, connecting to a battery-powered motor with two eccentric wheels,transforming rotation to vibration. The vibration can create an impactto the skin through a plurality of microneedles mounted on top of theexchangeable head. The frequency of vibration depends on rotation speedand mass distribution of the eccentric wheels and can be in the range ofabout 10 Hz to about 50000 Hz. In some embodiments, the frequency rangecan be between about 1000 and about 8000 Hz. An ordinary artisan candesign and make an applicator accordingly. Some examples of designing anapplicator for various uses are described in U.S. Pat. Nos. 390,089;1,512,981; 1,657,312; 1,683,851; 1,780,757; 1,790,962; 1,900,609;2,411,196; 4,237,911; 4,979,525; 5,054,149; 5,095,924; 5,215,193;5,328,682; 5,713,492; 5,738,122; D416,387; 6,092,252; and 6,220,253, thecontents of which are incorporated herein by reference in theirentirety.

In some embodiments, the applicator for mechanical skin treatmentcomprises:

(a) a housing having a plurality of walls defining an interior space,the interior space having an upper opening permitting selective accessto the interior space of the housing, a cover member being removablycouplable to the housing such that the cover is for closing the upperopening of the interior space of the housing; and

(b) a plurality of microneedle head portion connected to a base portionbeing removably insertable into the interior space of the housing, eachof the applicators being adapted for aiding a user to treat skin;

wherein the plurality of the applicator including a microneedle arrayassembly comprising:

-   -   (i) the microneedle array assembly being adapted for selectively        treating skin,    -   (ii) the microneedle assembly having a head portion and a base        portion, the head portion being selectively couplable to the        base portion such that the base portion is insertable into the        interior space of the housing, the base portion of the        microneedle array assembly having a pair of depressions, each of        the depressions extending along a portion of a length of the        base portion, one of the depressions being positioned opposite        the other of the depressions such that the depressions are        adapted for receiving finger tips of a hand of the user for        inhibiting slipping of the base portion from the hand of the        user of the applicator.

In some embodiments, the base portion of the applicator described abovecan further comprises a motor assembly being positioned in the baseportion, the head portion having a drive assembly being positioned inthe head portion, the drive assembly being operationally coupled to abase portion, the base portion outwardly extending from an upper end ofthe head portion, the motor assembly being operationally coupled to thedrive assembly such that the motor assembly is for actuating the driveassembly, the drive assembly being for oscillating the base portion whenthe drive assembly is actuated by the motor assembly.

In some embodiments, the applicator described above can further comprisea head portion having a plurality of microneedles extending from thebase portion, the microneedles being adapted for treat the skin when themicroneedle head portion is oscillated by the drive assembly.

In some embodiments, the applicator described above can further comprisea motor assembly having a motor, the motor having a shaft extending fromthe motor, the motor being for actuating the shaft, the shaft being foroperationally coupling to the drive assembly of the base and headportions such that actuation of the shaft actuates the drive assembly, apower source being operationally coupled to the motor such that thepower supply is for providing power to the motor.

In some embodiments, the applicator described above can include a heavyeccentric mass designed to produce vibration upon actuation of themotor, wherein the motor is actuated to bring the base and head portionsinto vibration so that skin treatment is practiced through the aid ofthe vibration, the microneedle application method comprising the stepsof:

predetermining respective weights of the electric applicator and theheavy eccentric mass as well as an eccentric location of the center ofgravity of the heavy eccentric mass; establishing an output of the motorat about 1000-15000 rpm in accordance with the predetermined conditions;producing a vibration of about 1000-15000 rpm by actuating the motor;

conducting the vibration to tips of microneedle on the head portion toincrease a pressing force acting along an axial direction of the baseand head portion by the use of a minute circular ring connecting to thehandle part and pressing against skin area need treatment.

In some embodiments, the applicator described above can further includea motor assembly having a switch, the switch being operationally coupledbetween the power supply and the motor, the switch being for controllingpower from the power supply to the motor.

Kits

In another aspect, the present subject matter relates to a kit fordelivering an agent to a mammal, comprising:

-   -   (a) a microdevice comprising a structure selected from        microneedles, microblades, microknives, and combinations        thereof;    -   (b) a wet formulation comprising a bioactive agent;    -   (c) an occlusive layer; and    -   (d) a mechanism to provide for a driving force sufficient to        form nanoconduits on the skin, lined with tissue displaced by        the driving force.

In this regard, the driving force can be, but is not limited to,ultrasound, iontophoresis, radio frequency, laser light, heat gradient,or a combination thereof.

In addition, the present kits may further comprises an applicator of themicrodevice for applying the microdevice to an area of skin of a mammal;and/or a driving force mechanism for driving the bioactive agent totransport through the stratum corneum of the area of skin into themammal. The driving force mechanism can comprise ultrasound, radiofrequency, heat gradient, laser light, iontophoresis device, or acombination thereof. In a preferred embodiment, the applicator is amechanical applicator.

The present kits are particularly useful in treating a mammal having amedical condition. Some potential medical conditions treatable by thepresent kits include, but are not limited to, chronic back pain, acancer, pre-surgery pain management, operation room pain management,cancer pain, post-surgery pain and lower back pain, and post-surgerypain management.

In this regard, the agent used in the kits can be, but is not limitedto, a natural or synthetic vaccine selected from the group consisting ofproteins, peptides, paclitaxel, docetaxel, vaccines, protein vaccines,peptide vaccines, gene vaccines, DNA vaccines, and combinations thereof.Further, the vaccine can be against influenza (flu), diphtheria,tetanus, pertussis (DTaP), measles, mumps, rubella (MMR), hepatitis B,polio, Haemophilus influenzae type b, chickenpox, tuberculosis, anthrax,yellow fever, rabies, AIDS, cancers, meningococcus, SARS, and/orcholera. In the alternative, the agent is a pain relieving agent. Inthis regard, the pain relieving agent can be lidocaine, tetracaine,dyclonine, or a combination of thereof.

The formulation used in the present kits can comprise elastic liposomesencapsulating the agent. The elastic liposomes can optionally comprisedeformable nanoparticles. In the alternative, the formulation in thepresent kits does not comprises elastic liposomes. In addition, theformulation can be a topical or systemic delivery formulation selectedfrom a skin patch, cream, ointment, or lotion. In a preferredembodiment, the formulation is a wet skin patch.

Active Agents

In one aspect, active agents or active substances that can be deliveredusing microdevices are therapeutic agents. The term “therapeutic agent”is used here to refer to active agent that can treat, prevent, andameliorate a body condition or skin condition that needs treatment. Alist of examples includes: drugs, vaccines, peptides, proteins, genes,DNAs, nutraceuticals and cosmetics. The drugs can be administeredtopically or systemically. Examples of the drugs as active agentsinclude, but not limited to antibiotics, hormones, steroids,anti-inflammatory drugs, protein drugs, DNA drugs whether natural orsynthesized, such as Recombinant Erythropoietin (rhEPO), Taxol®,Interferon-alpha-1b, Interferon beta, Interferon gamma, Emla®,Fluorouracil, Lidocaine, Salicylic acid, Pureriran, eflornithinehydrochloride, spironolactone, flutamide, insulin, nanoparticle drugs,Epidural, recombinant human parathyroid hormone, growth hormone,thyroid, cortisol, estrogen, progesterone, and testosterone. Examples ofvaccines active agents include, but not limited to: vaccine againstinfluenza (flu), diphtheria, tetanus, pertussis (DTaP), measles, mumps,rubella (MMR), hepatitis B, polio, Haemophilus influenzae type b,chickenpox, tuberculosis, anthrax, yellow fever, rabies, AIDS, cancers,meningococcus, SARS and cholera. More examples of cosmetic substances asactive agents include, but not limited to: botllinum toxin type A,hyaluronic acid and its derivatives, acetyl hexapeptide-3, vitamin A,vitamin C, vitamin E, alpha-hydroxyacids, collagen and hormones.Diagnostic reagents are also included. Examples include, but not limitedto, quantum dots, functionalized nanoparticles, magnetic particles fordiagnostic purpose.

The dosage of the agent can vary according to the medical conditions.The effective amount of an agent that has been well established in theart can be publicly available. Such information can be obtained from theU.S. Food and Drug Administration (FDA), e.g., FDA website. For example,LidoDerm® publishes this type of information.

In some embodiments, the agent is a pain relieving drug for neuropathicor nociceptive pain management. Such pain relieving drug includes, butis not limited to, Lidocaine; Prilocaine, Tetracaine, Ibuprofen;Acetaminophen; Capsaicin; EMLA®; Tramadol (Ultram); Gabapentin, Tramadolhydrochloride, Corticosteroids, Sufentanil, Clonidine, Bupivacaine,Tricyclic antidepressants, opioid analgesics such as morphine,Hydromorphone, naloxone (Narcan), Talwin, Nubain, Stadol, Fentanyl,Meperidine, Hydrocodone, Codeine, Oxycodone; non-selective NSAIDs suchas Celecoxib (Celebrex), rofecoxib (Vioxx), valdecoxib (Bextra); orcombinations thereof. In some embodiments, the pain relieving drugdescribed herein can specifically include any of the drug/agents listedherein.

In some embodiment, the active agent can be muscle relaxants, whichinclude, but are but not limited to, Benzodiazepines; Methocarbamol;Carisoprodol; Chlorzoxazone; Metaxalone; Cyclobenzaprine, orcombinations thereof. In some embodiments, the muscle relaxantsdescribed herein can specifically exclude any of the drug/agents listedherein.

Drug Delivery

In one aspect, the present subject matter provides a device 10 fordelivery of therapeutic active agent as defined above across the skinbarrier, stratum corneum layer. Once the substances pass the stratumcorneum, there is less resistance for the substances to diffuse into thesubsequent layers of the skin: epidermis and dermis. The substances willbe absorbed by micro blood vessels and lymphatics in the dermis layerand delivered to entire human body. Microdevices disclosed in thecurrent subject matter can enhance through skin penetration of moleculesof molecular weight lower than 500 Dalton. In some embodiments,microdevices can also enable through skin transport of large moleculesof molecular weight higher than 500 Dalton. The molecular weight ofBovine Serum Albumin is 66,000 Dalton. The molecular weight of BotulinumToxin Type A is 150,000 Dalton and the molecular weight ofInterferon-Alpha-1b is 17,000 Dalton.

In this regard, the present systems permit the agent to permeate theskin at least 10 times faster than in a system where the formulation isapplied to an area of skin which does not contain any generatednanoconduits. In this regard, the agent can permeate the skin tocumulative amounts at least 10 times higher than in a system where theformulation is applied to an area of skin which does not contain anygenerated nanoconduits.

In some embodiments, the drug delivery of the present subject matter canbe achieved by preparing an area of skin to generate a prepared area ofskin and then applying an agent or drug to the prepared area of skin toallow a pre-defined amount of the drug or agent to pass through thestratum corneum of the prepared area of skin.

In some embodiments, the prepared area of skin can be prepared using adevice, e.g., a spring-powered mechanical applicator to applymicroneedles to an area of skin. The mechanical applicator can be anystructure or design and can cause a mechanical force to be applied tothe microneedle against the area of skin to generate pores or channelsin the stratum corneum in the area of skin in a pre-defined size anddepth. The size and depth of the pores or channels can facilitate therelease of controlled amount of an agent or drug through skin.

In some embodiments, the prepared area of skin can be further treatedusing an ultrasound device or a mechanical vibrator to applymicroneedles to an area of skin. The ultrasound device or mechanicalvibrator can cause a pre-set mechanical force to be applied to themicroneedle against the area of skin to generate pores or channels inthe stratum corneum in the area of skin in a pre-determined size anddepth. The size and depth of the pores or channels can provide forcontrolling the amount of an agent or drug of delivery. It is noteworthythat the ultrasound device or mechanical vibrator can be an effectiveway to perforate an elastic skin tissue to generate pores or channels ina pre-defined size and/or depth.

In some embodiments, the prepared area of skin can be prepared in apre-defined size or dimension (e.g., a dimension of 1 cm.times.1 cm)using an array of microknives or microblades by slicing or laceratingthe stratum corneum in an area of skin to generate nanochannels in apre-defined depth and/or dimension. The dimension and/or depth of thelaceration and the dimension of the prepared area of skin can providefor controlling the amount of an agent or drug.

Allowing an agent or drug to pass through the stratum corneum of aprepared area of skin can be achieved by a variety of mechanisms. Forexample, the allowing can be achieved by diffusion of the agent or drugfrom a topical composition (e.g., a formulation such as lotion, cream,gel patch, ointment or skin patch) into the body of a patient or uservia the prepared area of skin. In some embodiments, the allowing can beachieved by a driving mechanism, for example, iontophoresis,sonophoresis, radiofrequency (RF) or heat or a combination of these toactively drive agents through the skin.

Iontophoresis, sonophoresis, radiofrequency (RF) or heat are welldeveloped mechanisms for promoting or enhancing drug delivery. Someexamples of iontophoresis systems in drug delivery are described inwebsites online. Some examples of sonophoresis systems in drug deliveryare described in Becker B, Helfrich S, Baker E, et al. Ultrasound withtopical anesthetic rapidly decreases pain of intravenous cannulation.Academic Emergency Medicine 2005; 12:289-295; Katz N, Shapiro D,Herrmann T, et al., Rapid onset of cutaneous anesthesia with EMLA creamafter pretreatment with a new ultrasound-emitting device. Pain TrialsCenter, Brigham and Women's Hospital, Boston, Mass.; Mitragotri S, KostJ, Low frequency sonophoresis: A Review. Advanced Drug Delivery Reviews2004; 56:589-601.

Topical or Systemic Delivery of Cosmetic Substances

It is known to one in the art that certain substances have specificfunctions as cosmetics. For example, Botulinum Toxin Type A is a toxinthat blocks neuromuscular transmission when it is injected in smallamounts (e.g., 10 units per 0.1 ml injection volume) into specificmuscles to treat and reduce wrinkles on the face. The maximum dosagerecommended as a single injection for any one muscle at any spot is 25units. If overdosed or the injection is incorrectly performed, thepatient can be left with an immobile face or droopy eyelids till theeffect of the injection wears off. The side effects include numbness,swelling and headaches. Administered through microdevices disclosed inthe current subject matter, it is possible to provide a controlledrelease of Botulinum Toxin Type A and keep an optimal localconcentration to achieve the best result while minimizing the sideeffects. In a preferred embodiment of this subject matter, gel patchwith botulinum toxin type A is applied to the skin pre-treated withmicroneedle array. No through skin transport was observed withoutapplication of microdevices while significant through skin transport ofbotulinum toxin type A was observed using the said microdevice. Moreexamples were provided in the above “active agents” section.

Transdermal delivery of an agent through skin treated by the microdevicedescribed herein has less dependency on molecular weight of the agent.Using the methods described herein, practically, any cosmetic substancescan be delivered using microdevices herein. Local concentration can beadjusted through loading and composition for controlled release, as wellas a combination of microneedle height, density, size and shape. In oneembodiment of this subject matter, one can deliver hyaluronic acid gelthrough diffusion enhanced by microdevices. Hyaluronic acid is asubstance that exists naturally in the body. A major important functionof hyaluronic acid is to carry and bind water molecules. Stabilizednon-animal hyaluronic acid does not contain animal protein and does notrequire a skin test prior to treatment. It is thus a preferredembodiment of this subject matter to use microdevices to deliverylocally stabilized non-animal hyaluronic acid to treat wrinkles andfacial lines.

Yet, in a further embodiment of this subject matter, one can locallydelivery collagen by microneedles, e.g., for allergic skin test andcontrolled release of collagen into the skin.

Yet, another embodiment of this subject matter is to provide for localdelivery of acetyl hexapeptide-3. This molecule is a non-toxic,non-irritant compound that modulates the excessive stimulation of thefacial muscles, relaxing facial tension and it can reduce and preventthe formation of new wrinkles due to over-stimulation of facial muscles.More examples include but not limited to: vitamin A, vitamin C, vitaminE, alpha-hydroxyacids, hormones, or combinations thereof.

Delivery of Vaccines

In some embodiments, the microdevice provided herein can be used fortopical or systemic delivery of vaccines below the stratum corneumlayer. The type of vaccines includes conventional vaccines as well asprotein, peptide, DNA vaccines and the like as previously described.Vaccination can be performed by treating a skin site with themicrodevice and then delivering a vaccine composition to a user.

Delivery of Large Molecules

In some embodiments, the microdevice provided herein can be used fortopical or systemic delivery of drug with large molecules. The drug canbe a protein or peptide. In some embodiments, the drug can be a chemicaldrug with a relatively high molecular weight. As used herein, the termlarge molecule refers to a drug having a molecular weight higher thanabout 300 Daltons. For example, the molecule can have molecular weighthigher than about 500 Daltons, higher than about 1000 Daltons, higherthan about 5,000 Daltons, higher than about 10,000 Daltons, higher thanabout 20,000 Daltons, higher than about 50,000 Daltons, higher thanabout 100,000 Daltons, higher than about 200,000 Daltons, higher thanabout 500,000 Daltons, or higher than about 1,000,000 Daltons.

In some embodiments, the drug can be paclitaxel, docetaxel, insulin,Recombinant Erythropoietin (rhEPO), Interferon-alpha, Interferon beta,Interferon gamma, nanoparticle drugs, recombinant human parathyroidhormone, growth hormone, thyroid, cortisol, estrogen, progesterone, andtestosterone. Examples of vaccines active agents include, but notlimited to: vaccine against influenza (flu), diphtheria, tetanus,pertussis (DTaP), measles, mumps, rubella (MMR), hepatitis B, polio,Haemophilus influenzae type b, chickenpox, tuberculosis, anthrax, yellowfever, rabies, AIDS, cancers, meningococcus, SARS and cholera. Examplesof cosmetic substances as active agents include, but not limited to:botulinum toxin type A, hyaluronic acid and its derivatives, acetylhexapeptide-3, vitamin A, vitamin C, vitamin E, alpha-hydroxyacids,collagen and hormones. Diagnostic reagents are also included. Examplesinclude, but not limited to, quantum dots, functionalized nanoparticles,magnetic particles for diagnostic purpose.

Pain Management

In some embodiments, the microdevice described herein can be used forpain management. The microdevice can be used to facilitate transdermaldelivery of a pain relieving agent or a combination of them so as totreat, reduce or prevent pain. In some embodiments, a skin site can betreated with the microdevice and then a pain relieving agent or drugcomposition can be applied to the treated site, allowing transdermaldelivery of these agents to a user.

The pain relieving agent can be any pain relieving agent approved by FDAor used in medical practice elsewhere in the world. In some embodiments,the pain relieving drug can be, but are not limited to, NSAIDs, COX-2inhibitors, steroids, muscle relaxants. Specifically, such as Lidocaine;Prilocaine, Tetracaine, Ibuprofen; Acetaminophen; Capsaicin; EMLA®;Tramadol (Ultram); Gabapentin, Tramadol hydrochloride, Corticosteroids,Sufentanil, Clonidine, Bupivacaine, Tricyclic antidepressants, opioidanalgesics such as morphine, Hydromorphone, naloxone (Narcan), Talwin,Nubain, Stadol, Fentanyl, Meperidine, Hydrocodone, Codeine, Oxycodone;non-selective NSAIDs such as Celecoxib (Celebrex), rofecoxib (Vioxx),valdecoxib (Bextra); or combinations thereof. In some embodiments, thepain relieving drug described herein can specifically exclude any of thedrug/agents listed herein.

The pain management can be carried out according to a management regimeprescribed by a treating doctor. For example, in some embodiment, thepain management is chronic or acute pain management. The pain managementregime can be but not limited to, lower back pain, post-herpeticneuralgia, cancer pain, diabetic neuropathy, phantom limb pain, spinalstenosis/sciatica, spinal mets, HIV pain, post-surgery pain, pre-surgerypreparation, operation room pain management, pain caused invasivemedical procedures such as needle injection, cannulation.

Different from prior art, the current subject matter involves topical orsystemic delivery of pain relieve agent to deep tissues throughassistance of a combination of active transdermal delivery methods suchas sonophoresis, iontophoresis, laser ablation, radio frequency or heattreatment after the startum corneum are treated with the saidmicrodevices.

In another aspect, the present systems and methods are useful fortreating cancer.

Controlled Release

The microdevices herein preferably deliver drug molecules through skinat a rate that is sufficient to maintain a therapeutic usefulconcentration in plasma. The size, density, shape and length of themicrodevices can be adjusted to meet the delivery requirement. Themicrodevices can be further coated with a composition that containsactive therapeutic molecules, or vaccines, or cosmetic substances,together with polymer binders such as chitosan, carbopol 934P, celluloseand starch to form a dry film. Additional additives of binders, rheologymodifiers, surface active agents, stabilizer, rehydration agents may beused. The special composition can control the dissolve rate of theactive drug molecule and regulate the drug release rate. Themicrodevices may be integrated with embedded microfluidic channels thatconnect to microreservoirs.

In this regard, the present the methods result in a plateau plasmaconcentration of agent, wherein the plateau is preferably maintainedwithin 80% of the peak concentration from 10 hours after first contactand up to at least 24 hours after first contact. The plateau can bemaintained within 80% of the peak concentration from 10 hours afterfirst contact and up to at least 48 hours after first contact.

Accordingly, the agents herein have a “drug permeation”, meaning as theamount of agent (mg, or mmol) diffused across the skin barrier within adefined time.

Occlusive Layer

In some embodiments, the method of delivering an agent, or a combinationof agents may include applying an occlusive layer. The occlusive layermay be applied over the applied agent and directly on the prepared areaof skin, or the area of skin, such that the occlusive layer prevents airfrom coming into contact with the prepared area of skin following theremoval of the applicator and microdevice from the skin. The occlusivelayer is advantageous for preventing evaporation of the agent orcombination of agents, and most importantly, allows for increasedpenetration of an active agent across the skin. The occlusive layer isuseful for preventing evaporation of the wet formulation and providesincreased penetration of the active agent across the skin.

In some embodiments, an occlusive layer is applied directly on theprepared area of the skin such that the occlusive layer prevents airfrom coming into contact with the prepared area of skin following theremoval of the applicator and microdevice. The prepared area of skin isgenerated by applying the applicator to an area of the skin, andsubsequently, the occlusive layer is applied directly on the abradedarea of skin, either with or without a wet formulation. The occlusivelayer may be placed directly on the prepared area of skin to prevent airor other fluids from entering the abraded skin area, other than the etformulation comprising the agent. In some embodiments, in order toprevent air from contacting the prepared area of skin, the occlusivelayer must contact the entire abraded area.

Applying the occlusive layer after applying a wet formulation comprisingthe agent to the prepared area of skin after the microdevice hasgenerated the plurality of nanopores or nanochannels in the preparedarea of skin substantially increases the rate of penetration of theagent. In fact, as described in more detail below, FIG. 2 shows thedifference for drug delivery between occlusive and non-occlusivetreatment following microneedle pre-treatment. From the data shown inFIG. 2, it is clearly evident that applying an occlusive layer aftermicroneedle pre-treatment significantly improves drug delivery since therate of penetration increases. When compared to non-occlusive treatmentafter microneedle pre-treatment, or even non-occlusive pretreatment withno microneedle pre-treatment, the rate of penetration is substantiallyless. In fact, the drug delivery data shown in FIG. 3 shows that thepresent method unexpectedly provides 72 hours of extended drug release.

In this regard, the data from the graph shown in FIG. 2 is provided inthe Table 1, which shows the effect of the occlusive layer onpenetration.

TABLE 1 Non- Non- Occlusively occlusively Occlusively occlusively withStandard with Standard without Standard without Standard Time(h)microneedles Deviation microneedles Deviation microneedles Deviationmicroneedles Deviation 2 0.07 0.07 0.08 0.08 0.06 0.09 0.11 0.06 4 1.941.41 0.32 0.46 0.18 0.11 0.35 0.30 8 3.74 1.02 1.80 0.91 0.54 0.42 0.540.16 12 5.13 1.55 2.60 0.85 0.88 0.49 0.76 0.16 24 10.33 3.43 5.07 1.881.71 0.83 1.40 0.22

The data in Table 1 shows comparative data of the percent penetration ofan active agent (docetaxel) in elastic liposomes across skin under fourdifferent sets of conditions, where the active is applied to the skinwith or without microneedle preparation of skin or use of an occlusivelayer:

(1) yes microneedle, yes occlusive layer;

(2) yes microneedle, no occlusive layer;

(3) no microneedle, yes occlusive layer; and

(4) no microneedle, no occlusive layer.

The data in Table 1 shows that adding an occlusive layer does not changethe percent penetration over 24 hours of the agent across skin notprepared with microneedles. The two data sets (“occlusively withoutmicroneedles” vs. “non-occlusively without microneedles”) showstatistically the same amount of penetration. In other words, theevidence shows that adding an occlusive layer does not increase thepenetration of the agent across unprepared skin.

Further, FIG. 2 shows that adding an occlusive layer to skin preparedwith microneedles unexpectedly and significantly increases the percentpenetration of the active across the prepared skin. This unexpectedincrease in penetration is due to the combination of the presence ofmicroneedle prepared skin and adding an occlusive layer to themicroneedle prepared skin.

FIG. 6 shows a graph of Trans-Epidermal Water Loss with or withoutmicroneedle application. In the graph, the X-axis represents the time inseconds and the Y-axis represents the Trans-Epidermal Water Loss (TEWL).The diamond shaped data points represent the TEWL baseline, and thesquare shaped data points represent the increase of TEWL after thetreatment with the present microdevice. The curve of the square shapeddata points decreases over time and eventually merges with the diamondshaped data points at about 200 seconds. This indicates that the skinbarrier was initially compromised and penetrated by the microdevice andthe skin quickly recovers in about 120-200 seconds or 20-30 minutes.

FIG. 7 shows a graph of serum insulation concentration with an occlusivelayer applied. In particular, the graph shows the prolife of Novolin R®serum insulin concentration vs. time in a diabetic rat after theadministration of insulin by the present microdevice. The serumconcentration reached 110±5.37 μIU/ml and stayed relatively constant atthis level when the occlusive layer was applied. This indicates that thedelivery channels were kept open to meet the basal insulin deliveryneed. The serum concentration rapidly dropped after the removal of theocclusive layer, indicating that the pores closed and the insulindelivery source was cut off.

Before the filing of this application, it was generally considered thatthe skin barrier rapidly restores resulting in a shorter period of drugdelivery. For example, Yang et al., “Topical stratum corneum lipidsaccelerate barrier repair after tape stripping, solvent treatment andsome but not all types of detergent treatment”, Br. J. Dermatol, 1995November; 133(5):679-85 (hereinafter “Yang”) and Bashir et al.,“Physical and physiological effects of stratum corneum tape stripping”,Skin Res. Technol. 2001 February; 7(1):40-8 (hereinafter “Bashir”),teach various means of disrupting the barrier function of the strateumcorneum (SC) have been extensively described, including tape-strippingand acetone treatment. Specifically, tape stripping removes the SCmechanically, while acetone treatment extracts lipids from the SC.Restoration of barrier function occurs in a similar amount of timefollowing tape stripping and acetone treatment. Notwithstanding the typeof method for penetrating the skin, the pores of the skin generally stayopen for a very short period of time providing a limited window for drugdelivery. The present microdevice and method overcomes thesedeficiencies. The present subject matter significantly improves drugdelivery since the rate of penetration increases and allows extendeddrug delivery, i.e., 72 hours as shown in FIG. 3.

The Integrated Sensors

It is another aspect of the subject matter to provide a device in whichclinical biosensor and/or sensor arrays are fabricated in the closevicinity of these HARMS structures. For example, microneedle can collectan extremely low sample volume of body fluids from a patient and allowrapid point-of-care analysis of body fluids. In one embodiment, thesample volume extracted is below 0.1 microliter, typically around 0.01microliter.

Methods for HARMS Fabrication

The HARMS were fabricated using MEMS (Micro-Electro-Mechanical Systems)microfabrication technology. The typical fabrication process involvedlithography, wet etch and dry etch, thin film deposition and growth,electroplating, as well as injection molding and hot embossing. Oneexample of fabrication method was to use Bosch process that allowed deepSi etch. It formed HARMS suitable either as device body or mold forfurther processing. The aspect ratio was higher than 5:1, independent tofeature size and pattern shape as long as the features can be defined bylithography. Another fabrication method was KOH or TMAH wet etch ofsingle crystal Si substrate that is <100> orientation or <110>orientation. Yet another fabrication method was using HF solution toelectrochemically form porous Si structures. Metals was used for thefabrication of HARMS through a maskless process called electropolishingstarting from a structure fabricated by traditional machining methodssuch as cutting, electro-discharge machining, milling, grinding,polishing and drilling. Use of any single method herein or a combinationof these methods as further disclosed in the examples below led to theform of desired HARMS disclosed in the current subject matter.

EXAMPLES Example 1. Delivery of Docetaxel with Combination ofMicroneedle with Flexible Liposome Nanoparticles

FIGS. 2 and 3 showed the efficacy of transdermal delivery of agents ofthe present subject matter. In the test shown in FIGS. 2 and 3, an areaof skin was pre-treated with the microneedles described above. Then aformulation of a fluorescence labeled albumin (molecular weight is66,000) was applied and successfully transport them through skin (FIG.3). The pore formed by the microneedles will not completely be closedwithin 72 hours after application of the microneedles. FIG. 2 showsPenetration (%) of docetaxel in elastic liposomes with or withoutmicroneedle.

Example 2. Delivery of Interferon with Combination of Microneedle

FIG. 4 shows delivery of interferon via different methods. Theeffectiveness of various delivery methods was assessed by measurement ofinterferon activity: (a) microneedle with a wet interferon gel on themicroneedles, (b) microneedle with a wet interferon gel patch on skinpre-treated with microneedles, (c) subcutaneous injection, and (d) wetinterferon gel without microneedle as control sample.

FIG. 5 shows delivery of interferon with a dry formulation. As FIG. 5shows, when the patch is dried, the delivery rate dropped dramatically.

In sum, FIGS. 4 and 5 show that delivery of interferon using a dry patchis less effective as it is using a wet patch.

While particular embodiments of the present subject matter have beenshown and described, it will be obvious to those skilled in the art thatchanges and modifications can be made without departing from thissubject matter in its broader aspects. Therefore, the appended claimsare to encompass within their scope all such changes and modificationsas fall within the true spirit and scope of this subject matter.

1-15. (canceled)
 16. A kit for delivering an agent to a mammal,comprising: a microdevice comprising a structure selected frommicroneedles, microblades, microknives, and combinations thereof; a wetformulation comprising a bioactive agent; a mechanism to provide for adriving force to the microdevice; and an occlusive layer.
 17. The kit ofclaim 16, wherein the driving force is ultrasound, iontophoresis, radiofrequency or heat gradient.
 18. The kit of claim 16, further comprisingan applicator of the microdevice for applying the microdevice to an areaof skin of a mammal.
 19. The kit of claim 16, further comprising adriving force mechanism for driving the bioactive agent to transportthrough the stratum corneum of the area of skin into the mammal.
 20. Thekit of claim 16, wherein the mammal has a medical condition, wherein theagent is a natural or synthetic vaccine selected from the groupconsisting of proteins, peptides, paclitaxel, docetaxel, vaccines,protein vaccines, peptide vaccines, gene vaccines and DNA vaccines, andwherein the vaccine is against influenza (flu), diphtheria, tetanus,pertussis (DTaP), measles, mumps, rubella (MMR), hepatitis B, polio,Haemophilus influenzae type b, chickenpox, tuberculosis, anthrax, yellowfever, rabies, AIDS, cancers, meningococcus, SARS and cholera.
 21. Thekit of claim 16, wherein the formulation comprises elastic liposomesencapsulating the agent.
 22. The kit of claim 16, wherein theformulation does not comprises elastic liposomes.
 23. The kit of claim21, wherein the elastic liposome comprises deformable nanoparticles. 24.The kit of claim 16, wherein the formulation is a topical or systemicdelivery formulation selected from a skin patch, cream, ointment, orlotion.
 25. The kit of claim 16, wherein the driving force mechanismcomprises ultrasound, or radio frequency, heat gradient or iontophoresisdevice.
 26. The kit of claim 16, wherein the agent is a pain relievingagent.
 27. The kit of claim 26, wherein the pain relieving agent islidocaine, tetracaine, dyclonine or a combination of thereof, andwherein the formulation is lotion, cream, gel patch, ointment or skinpatch comprising lidocaine, tetracaine, dyclonine or a combinationthereof.
 28. The kit of claim 16, wherein the formulation is a topicalor systemic delivery formulation selected from a skin patch, cream,ointment, or lotion.
 29. The kit of claim 16, wherein the applicator isa mechanical applicator.
 30. The kit of claim 16, wherein theformulation is a wet skin patch.